[feature] Subscription Service Price Tracker with Interactive Stock-Style Charts and Proactive Alerts

[jacob-kraniak]

Title: Feature Proposal: Subscription Service Price Tracker with Interactive Stock-Style Charts and Proactive Alerts

Is your feature request related to a problem? Please describe.

Many individuals monitor recurring subscription costs—particularly for streaming and media services such as Netflix, Hulu, YouTube TV, Spotify, and similar platforms—to track long-term price inflation, anticipate increases, and evaluate ongoing value. While changedetection.io provides excellent general website change detection and single-product price monitoring, it lacks specialized support for subscription ecosystems, including:

• Curated presets for popular subscription services and their tiered plans
• Rich, interactive historical trend visualization comparable to stock price trackers or PCPartPicker component histories
• Multi-service and multi-tier comparison within a single view
• Contextual annotations from official vendor announcements
• Advanced alerting tied to personal budget thresholds and cancellation guidance

Current price detection is well-suited to e-commerce but does not fully address the characteristics of subscription pricing: infrequent yet significant discrete increases, multiple plan tiers per service, regional variations, and the value of long-horizon (5–10+ year) historical context.

Describe the solution you'd like

Introduce a "Subscription Price Tracker" module or dedicated mode that extends the existing price detection and notification capabilities with subscription-specific features. The proposed components are:

1. Pre-configured Subscription Presets
   Deliver a curated library of URLs and selectors for major subscription services (e.g., Netflix, Hulu, YouTube TV, Spotify, Disney+, Amazon Prime Video, Apple TV+, Paramount+, others).

   • Support multiple plan tiers per service (Basic, Standard, Premium, Family, etc.)
   • Enable straightforward user extension for additional services or regional pricing pages

2. Historical Data Seeding & Import
   Allow one-time import of verified historical pricing data spanning 5–10+ years from authoritative sources, including:

   • CableTV.com streaming price tables
   • FinanceBuzz.com historical summaries
   • Cross-verified Wikipedia timelines
   • Official company newsroom and investor-relations archives
     This would seed the history database immediately, enabling meaningful trend analysis from initial setup while ongoing watchers capture future changes.

3. Interactive Stock-Style Visualization for Price Trends
   Add a dedicated visualization panel or dashboard tab featuring flexible, interactive charts modeled after stock price trackers:

   • Supported chart types: Line (clean trend overview), Area/Mountain (shaded to highlight cumulative change), Candle (adapted for discrete price steps, showing magnitude of increases), OHLC bar (where useful for emphasizing adjustment points)
   • Core interactivity: Zoom, pan, crosshair tooltips with exact date, price, and percentage change; toggle between monthly, quarterly, and yearly aggregation
   • Multi-series comparison: Overlay multiple services and plan tiers in the same chart window (e.g., Netflix Premium, Hulu With Ads, Spotify Family) for direct side-by-side analysis of inflation trajectories
   • Visual controls: Color-coded legends, series visibility toggles, synchronized axes across overlaid datasets
   • Annotations: Place vertical markers or callouts at significant price changes, linking to (or summarizing) corresponding vendor blog posts or press releases (e.g., “Netflix Jan 2025 increase: +$2–3 for content investment”)

4. Enhanced Alerting & Budget Management Tools
   Extend the notification framework with subscription-oriented triggers:

   • Email, webhook, or integration alerts when a price increase exceeds a user-defined percentage or absolute threshold
   • “Budget cap” notifications suggesting cancellation or review when a plan surpasses a personal maximum (e.g., “Netflix Premium > $25 → consider lower-cost alternatives”)
   • Future extension: Neutral, community-sourced recommendations for comparable lower-priced services

Describe alternatives you've considered

• Static articles and tables (CableTV.com, FinanceBuzz, PCMag) offer historical data but provide no real-time monitoring, interactive filtering, multi-service comparison, or proactive alerts
• Personal subscription managers (Wallos, SubTrackr) track individual expenses but do not scrape public pricing pages or generate cross-vendor trend visualizations
• General change-detection tools focus on products rather than subscription models with tiered plans and infrequent updates

Additional context

This feature would meaningfully expand changedetection.io’s utility for consumers facing subscription cost creep, while remaining fully self-hosted and privacy-respecting. It leverages existing strengths (price extraction, history storage, Playwright support, notifications) and can be delivered incrementally:

• Phase 1: Preset library + historical data import
• Phase 2: Multi-type charting engine with multi-series overlay support
• Phase 3: Advanced alerts, budget caps, and vendor announcement annotations

I am prepared to contribute selectors, import scripts, or visualization prototypes. If useful, I can supply initial wireframes or example selectors for priority services.

Thank you for considering this proposal. It would provide a powerful, community-oriented tool for subscription price transparency and cost-awareness.